From 1981 to 2009, NBC aired just three series in the Thursday 10 p.m. time slot: Hill Street Blues, L.A. Law and ER. Celebrated by critics and viewers alike, these were canonical dramas, series that represented network TV at its very best. Since ER flatlined in April 2009, NBC’s showcase has become a junk shop; in the last seven months alone, the network has run three dramas in the hour, a string of flops that averaged a 1.2 rating in the adults 18-to-49 demo.

Don’t think for a minute that the problem is exclusive to NBC or Thursday night. Of the 11 new 10 p.m. series introduced this season, seven have failed to crack the 2.0 mark in the demo and eight will not return for a second run. The lone series in the time slot that has been renewed for the 2012-13 campaign, NBC’s Smash, is averaging a 2.6 in the dollar demo, making it the hour’s second biggest draw behind CBS’ Hawaii Five-0 (3.0).

The last time a 10 p.m. drama finished among broadcast’s top 10 was during the 2006-07 campaign, when Lost averaged a sturdy 6.0 rating on ABC. Today, nothing at 10 p.m. on any broadcast network comes anywhere near that number. Like the passengers on Oceanic Flight 815, the 10 p.m. broadcast viewer has vanished.

Although there are any number of hypotheses to explain why 10 p.m. has become a ghost town, a unified theory has yet to be advanced. That said, many programmers believe the DVR is to blame for a good part of the erosion. According to Leichtman Research Group, time-shifting technology has worked its way into 44 percent of all U.S. TV homes, creating a new ruling class of 50 million amateur schedulers.

“The ‘DVR channel’ is the No. 1 network at 10 o’clock, by a two-to-one margin,” said FX president John Landgraf. “Viewers are using the hour to catch up on the shows, and it’s eating into the live ratings. As more and more dramas fail, there is no longer enough off-net material available to sustain the cable programming model.”

While live viewership accounts for 80 percent of all TV consumption, cable series tend to get a bigger boost from the DVR. Live-plus-seven-day data suggests that cable ratings earn a 50 percent lift from time-shifting, while broadcast sees a 36 percent bump. That said, playback does not seem to be taking a bite out of cable series like Jersey Shore and Pawn Stars, which flourish at 10 p.m.

Gizmos aside, broadcast is getting its clock cleaned in the prestige department. “There’s no longer anything on broadcast in that time slot that stands out,” said Brad Adgate, Horizon Media’s svp of research. “The watercooler shows like Mad Men, the shows that win awards and attract younger viewers, are all on cable.”

As more young viewers turn their attention to cable, broadcast has become all but ossified. Season to date, the median age of the top 10 p.m. programs on broadcast is 56 years, or 24 months beyond the gray fringe of the 25-to-54 demo. By comparison, FX’s Emmy-winning drama Justified boasts a median age of 46 years.

Some argue that the 10 p.m. curse isn’t a pandemic. “I have no problems with CBS,” said one TV buyer. “Their procedurals deliver, and there aren’t too many soft spots in their lineup.”

From 1981 to 2009, NBC aired just three series in the Thursday 10 p.m. time slot: Hill Street Blues, L.A. Law and ER. Celebrated by critics and viewers alike, these were canonical dramas, series that represented network TV at its very best. Since ER flatlined in April 2009, NBC’s showcase has become a junk shop; in the last seven months alone, the network has run three dramas in the hour, a string of flops that averaged a 1.2 rating in the adults 18-to-49 demo.

Don’t think for a minute that the problem is exclusive to NBC or Thursday night. Of the 11 new 10 p.m. series introduced this season, seven have failed to crack the 2.0 mark in the demo and eight will not return for a second run. The lone series in the time slot that has been renewed for the 2012-13 campaign, NBC’s Smash, is averaging a 2.6 in the dollar demo, making it the hour’s second biggest draw behind CBS’ Hawaii Five-0 (3.0).

The last time a 10 p.m. drama finished among broadcast’s top 10 was during the 2006-07 campaign, when Lost averaged a sturdy 6.0 rating on ABC. Today, nothing at 10 p.m. on any broadcast network comes anywhere near that number. Like the passengers on Oceanic Flight 815, the 10 p.m. broadcast viewer has vanished.

Although there are any number of hypotheses to explain why 10 p.m. has become a ghost town, a unified theory has yet to be advanced. That said, many programmers believe the DVR is to blame for a good part of the erosion. According to Leichtman Research Group, time-shifting technology has worked its way into 44 percent of all U.S. TV homes, creating a new ruling class of 50 million amateur schedulers.

“The ‘DVR channel’ is the No. 1 network at 10 o’clock, by a two-to-one margin,” said FX president John Landgraf. “Viewers are using the hour to catch up on the shows, and it’s eating into the live ratings. As more and more dramas fail, there is no longer enough off-net material available to sustain the cable programming model.”

While live viewership accounts for 80 percent of all TV consumption, cable series tend to get a bigger boost from the DVR. Live-plus-seven-day data suggests that cable ratings earn a 50 percent lift from time-shifting, while broadcast sees a 36 percent bump. That said, playback does not seem to be taking a bite out of cable series like Jersey Shore and Pawn Stars, which flourish at 10 p.m.

Gizmos aside, broadcast is getting its clock cleaned in the prestige department. “There’s no longer anything on broadcast in that time slot that stands out,” said Brad Adgate, Horizon Media’s svp of research. “The watercooler shows like Mad Men, the shows that win awards and attract younger viewers, are all on cable.”

As more young viewers turn their attention to cable, broadcast has become all but ossified. Season to date, the median age of the top 10 p.m. programs on broadcast is 56 years, or 24 months beyond the gray fringe of the 25-to-54 demo. By comparison, FX’s Emmy-winning drama Justified boasts a median age of 46 years.

Some argue that the 10 p.m. curse isn’t a pandemic. “I have no problems with CBS,” said one TV buyer. “Their procedurals deliver, and there aren’t too many soft spots in their lineup.”